I -- Field of the Invention
This invention relates to a manually operated pump for dispensing the contents of a container.
II -- Description of the Prior Art
A wide variety of dispensing pumps have found commercial acceptance for dispensing a product from a container. The typical pump includes a vertically reciprocal finger actuated plunger, that causes product to pass through a dip tube, enter a pump chamber and exit through a nozzle or outlet, according to the prescribed pumping cycle and predetermined opening and closing of both inlet and outlet valves.
Similarly, trigger actuated pumps gained in popularity with pumping being achieved by pressing and releasing a laterally disposed trigger mechanism.
Dispensing pumps of the prior art have been constructed to provide a fixed volume of product to be discharged per stroke. If a different volume per stroke was desired a new set of tooling for manufacturing the pump would be required which could be extremely expensive.
In addition, pumps of the foregoing type require a relatively larger number of complex parts with consequent expense both in manufacture and assembly. Thus, there exists a need fo dispensing pumps that are relatively simple and reliable with a substantially reduced number of parts, each individually simple and inexpensive to manufacture and assemble.
The need for reliable and less costly pumps for dispensing products, particularly, those that are petroleum based and/or chemically reactive with regard to the pump materials has increased; and it is become acute as pumps replace aerosol dispensing packages that are being withdrawn because of fluorocarbon propellants with their predicted effect on the environment. In addition, such criticism has served to make the consumer aware of the inherent economy and convenience of pump type dispensers.
While the pumps disclosed in the above referenced patent application provides an effective solution to solving the shortcomings of the prior art dispensing pumps, it remains a continuing desire of this industry to decrease manufacturing costs and upgrade the construction, performance and reliability, as well as enhance and widen the application of dispensing pumps for an ever-increasing variety of substances and materials with spray patterns heretofore sought but never achieved by pumps.